Insufficient or excessive respiratory effort during acute hypoxemic respiratory failure (AHRF) increases the risk of lung and diaphragm injury. We sought to establish whether respiratory effort can be optimized to achieve lung- and diaphragm-protective (LDP) targets (esophageal pressure swing − 3 to − 8 cm H2O; dynamic transpulmonary driving pressure ≤ 15 cm H2O) during AHRF. In patients with early AHRF, spontaneous breathing was initiated as soon as passive ventilation was not deemed mandatory. Inspiratory pressure, sedation, positive end-expiratory pressure (PEEP), and sweep gas flow (in patients receiving veno-venous extracorporeal membrane oxygenation (VV-ECMO)) were systematically titrated to achieve LDP targets. Additionally, partial neuromuscular blockade (pNMBA) was administered in patients with refractory excessive respiratory effort. Of 30 patients enrolled, most had severe AHRF; 16 required VV-ECMO. Respiratory effort was absent in all at enrolment. After initiating spontaneous breathing, most exhibited high respiratory effort and only 6/30 met LDP targets. After titrating ventilation, sedation, and sweep gas flow, LDP targets were achieved in 20/30. LDP targets were more likely to be achieved in patients on VV-ECMO (median OR 10, 95% CrI 2, 81) and at the PEEP level associated with improved dynamic compliance (median OR 33, 95% CrI 5, 898). Administration of pNMBA to patients with refractory excessive effort was well-tolerated and effectively achieved LDP targets. Respiratory effort is frequently absent under deep sedation but becomes excessive when spontaneous breathing is permitted in patients with moderate or severe AHRF. Systematically titrating ventilation and sedation can optimize respiratory effort for lung and diaphragm protection in most patients. VV-ECMO can greatly facilitate the delivery of a LDP strategy. Trial registration: This trial was registered in Clinicaltrials.gov in August 2018 (NCT03612583).

中文翻译：

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急性低氧性呼吸衰竭的肺和膈肌保护性通气策略：一项生理试验


急性低氧性呼吸衰竭 (AHRF) 期间呼吸用力不足或过度会增加肺和膈肌损伤的风险。我们试图确定在 AHRF 期间是否可以优化呼吸努力以实现肺和膈肌保护 (LDP) 目标（食道压力波动 − 3 至 − 8 cm H2O；动态跨肺驱动压 ≤ 15 cm H2O）。对于早期 AHRF 患者，一旦被动通气不被认为是强制性的，就会开始自主呼吸。系统地调整吸气压、镇静、呼气末正压 (PEEP) 和吹扫气流（接受静脉-静脉体外膜肺氧合 (VV-ECMO) 的患者）以实现 LDP 目标。此外，对难治性过度呼吸用力的患者进行部分神经肌肉阻滞（pNMBA）。在 30 名入组患者中，大多数患有严重的 AHRF； 16 需要 VV-ECMO。入组时完全没有呼吸困难。开始自主呼吸后，大多数人表现出高呼吸努力，只有 6/30 达到 LDP 目标。在滴定通气、镇静和吹扫气流后，LDP 目标在 20/30 内实现。使用 VV-ECMO（中位 OR 10，95% CrI 2, 81）和与动态顺应性改善相关的 PEEP 水平（中位 OR 33，95% CrI 5, 898）的患者更有可能实现 LDP 目标。对难治性过度用力的患者施用 pNMBA 耐受性良好，并有效实现了 LDP 目标。中度或重度 AHRF 患者在深度镇静下经常缺乏呼吸努力，但在允许自主呼吸时呼吸努力变得过度。系统地调整通气和镇静可以优化大多数患者的呼吸努力，从而保护肺和膈肌。 VV-ECMO可以极大地促进LDP策略的实施。试验注册：该试验于 2018 年 8 月在 ClinicalTrials.gov 上注册（NCT03612583）。